Primary epithelioid angiosarcoma of the mandibular gingiva: diagnostic pitfalls, about an unusual entity.

Primary angiosarcoma of the oral cavity is a rare malignant vascular neoplasm variably recapitulating endothelial cells and is generally associated with a worse prognosis. The epithelioid subtype is even uncommon in this localization. To our knowledge, only seven cases of primary oral epithelioid angiosarcoma have been reported until 2021. This histopathological variant is characterized by solid and sheet-like growth patterns that may be misinterpreted as other lesions with epithelioid cells. Herein, we present a new case of primary epithelioid angiosarcoma of the mandibular gingiva to discuss histopathological differential diagnoses and potential diagnostic pitfalls.

Pseudomyogenic Hemangioendothelioma Arising in the Maxillary Sinus, an Uncommon and Misdiagnosed Tumor: A Case Report.

Pseudomyogenic hemangioendothelioma (PMHE) is a rare vascular neoplasm with an intermediate to low-grade malignant potential. Only 5% of PMHEs occur in the head and neck. This tumor exhibits different histological patterns and mimics other vascular tumors, myoid tumors, or carcinomas. The distinction between these tumors can be a very challenging situation for pathologists. In this article, we report the first case, to our knowledge, of PMHE arising in the maxillary sinus, to highlight this uncommon entity and discuss differential diagnoses.